Theoretical Study of Khellin Derivatives as Corrosion Inhibitors Based on Density Functional Theory (DFT)

Abstract

Theoretical studies of Khellin in the presence of electron donor and electron-withdrawing groups as a corrosion inhibitor are investigated using the Density Functional Theory (DFT) with basis set B3LYP/6-31G (d, p) theory level with Gaussian software. This research focuses on the correlation between corrosion inhibition efficiency (EI%) and quantum chemical parameters such as EHOMO (Highest Occupied Molecular Orbital Energy), ELUMO (Lowest Unoccupied Molecular Orbital Energy), energy gap (ΔE), dipole moment (μ), absolute hardness (η), absolute softness (σ), the absolute electronegativity (χ), the fractions of electrons transferred from the inhibitor molecule to the metallic atom (ΔN), the electrophilicity index (ω), total energy (ET) and theoretical corrosion inhibition efficiency (EI %). The generated results show that the electron-donating groups increase the corrosion inhibition efficiency of Khellin in the sequence -NH2> -SH> -H> -NCH2> -NO2. The highest corrosion inhibition efficiency obtained about 98.40% proves that NH2-Khellin is the best corrosion inhibitor of iron. The Moleculer Dinamic (MD) simulation shows good interaction and strong binding energy between Khellin-NH2 and Fe (110) surface.